Methods for producing lower electrical isolation in electrochromic films

ABSTRACT

The present invention provides for an electroactive device having a first conductive layer, a second conductive layer, and one or more electroactive layers sandwiched between the first and second conductive layers. One or more adjacent layers of the electroactive device may include a physical separation between a first portion and a second portion of the adjacent layers, the physical separation defining a respective tapered sidewall of each of the first and second portions. The one or more adjacent layers may include one of the first and second conductive layers. The remaining layers of the electroactive device may be formed over the physical separation of the one or more adjacent layers. The remaining layers may include the other of the first and second conductive layers.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 120 to and is adivisional of U.S. application Ser. No. 14/095,308 entitled “Methods forProducing Lower Electrical Isolation in Electrochromic Films,” byKalweit et al., filed Dec. 3, 2013, which is assigned to the currentassignee hereof and incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to improvements in electroactive devicesand more particularly relates to improvements in solid-state, inorganicthin film devices.

One example of an electroactive device that the present inventionrelates to is an electrochromic device (“EC device”). Electrochromicmaterials and devices have been developed as an alternative to passivecoating materials for light and heat management in building and vehiclewindows. In contrast to passive coating materials, electroactive devicesemploy materials capable of reversibly altering their optical propertiesfollowing electrochemical oxidation and reduction in response to anapplied potential. The optical modulation is the result of thesimultaneous insertion and extraction of electrons and chargecompensating ions in the electrochemical material lattice.

EC devices have a composite structure through which the transmittance oflight can be modulated. FIG. 1 illustrates a typical five layersolid-state electrochromic device in cross-section having the fivefollowing superimposed layers: an electrochromic electrode layer (“EC”)14 which produces a change in absorption or reflection upon oxidation orreduction; an ion conductor layer (“IC”) 13 which functionally replacesan electrolyte, allowing the passage of ions while blocking electroniccurrent; a counter electrode layer (“CE”) 12 which serves as a storagelayer for ions when the device is in the bleached or clear state; andtwo transparent conductive layers (“TCLs”) 11 and 15 which serve toapply an electrical potential to the electrochromic device. Each of theaforementioned layers is typically applied sequentially on a substrate16. Such devices typically suffer from intrinsic and defect-inducedelectronic leakage (between the electrochromic stack layers) andelectronic breakdown.

Typically, electrical power is distributed to the electrochromic devicethrough busbars. FIG. 2 illustrates the electrochromic device of FIG. 1,in cross-section, having power supplied from two conductive elements,such as busbars 18 and 19. In order to prevent the busbars from shortingtogether, the busbars are electrically isolated from one another.Conventionally, this is done by scribing the TCLs 11 and 15. As shown inFIG. 2, the first (lower) TCL 15 is scribed at point P1, making thelower TCL 15 a discontinuous (i.e., physically separate) layer, andthereby preventing the busbars from shorting across the lower TCL 15.The width of the scribe at point P1 is typically on the order of 25microns or wider, while the length varies based on the width theparticular device being formed. Similarly, the second (upper) TCL 11 isscribed at point P3, making the upper TCL 11 also discontinuous, andthereby preventing the busbars from being shorted together across theupper TCL 11. Similar to the dimensions of the P1 scribe, the P3 scribeis typically on the order of 25 microns or wider, while the lengthvaries based on the width the particular device being formed.

In order for a solid state electrochromic device to function correctly,it is necessary to block electric current from passing between thebusbars of the electrochromic device directly, other than through thedesired electrochromic mechanism. Any electronic current that leaks orpasses through the electroactive layers serves to short out the requiredvoltage and inhibits the flow of ions through the electrochromic device.As such, leakage current due to intrinsic or defect-induced electronicleakage leads to compromises in device performance including a lowereddynamic range, non-uniform coloration, decreased ionic conductance,slower switching rates, and increased power consumption.

Merely increasing the thickness of the ion conductor layer may result ina reduction of leakage current, but at the expense of degraded opticalproperties, increased layer deposition time and cost, and reducedswitching rates. Likewise, adding dielectric layers to the stack mayreduce leakage current but at the cost of similar defects and possibleyield reduction. In general, the yield can be considered to be reducedevery time a substrate or other workpiece is cycled between thedeposition chamber and atmosphere, and vice versa. This is because dustand debris from the coating process—which are inevitably present in filmdeposition—are ‘blown’ around during purging, venting, and/or pumpdown,and can find its way onto the active layers, leading to defects in thefilm structure. Ideally, all the layers could be deposited in one singlecontinuous process step, i.e., one coating machine. However, depositingadditional dielectric layers could require transporting the workpiecebetween coaters to deposit the additional layers and then transportingthe workpiece back to resume fabrication of the above described ECstack. Such transportation, which could involve the workpiece exitingand reentering the deposition system and/or additional handling of theworkpiece, would significantly increase production time, increase thedevice's exposure to particles and other contaminants, and greatlyincrease the risk of damage (e.g., scratching, mishandling, etc.) of thedevice. Accordingly, it is desirable to reduce the amount of electronicleakage through an electrochromic device without resorting to a thickion conductor layer or additional dielectric layers so as to avoid thesecompromises in performance.

The above described challenges are not exclusive to electrochromicdevices. Any electroactive device having one or more functionalelectroactive layers sandwiched between top and bottom conductive layersmay present similar challenges if a conductive layer is scribed toprevent shorting across that conductive layer. For instance, scribingthe lower conductor layer, and optionally one or more of theelectroactive layers, of an electroactive device (e.g., anelectroluminescent device having aConductor/Insulator/Phosphor/Insulator/Conductor structure, an organiclight emitting diode (OLED) having a Conductor/Electron TransportLayer/Emitting Layer/Hole Transport Layer/Conductor structure, orphotovoltaic device having a Conductor/Electron Donor/P-NJunction/Electron Acceptor/Conductor structure, etc.) would create therisk or possibility of asperities, cracks, delamination, melt spots,and/or other defects along the scribe edge (e.g., within 5 microns ofthe upper edge of a P1 scribe). Stated another way, the above describedchallenges are a product of the melting and delamination characteristicsof the scribed conductive and electroactive layers, regardless of whatelectroactive device those layers are incorporated into.

Thus, it is desirable to reduce the amount of electronic leakage betweenthe portions of the transparent conductive layers of the electrochromicdevice while maintaining as high a yield as possible (e.g., conductingas few scribing steps during the cutting process as possible). Moregenerally, it is desirable to reduce the amount of electronic leakagebetween upper and lower (i.e., opposing) conductive layers in anyelectroactive device in which scribing performed during production ofthe device may lead to electronic leakage from delamination or meltingof the scribed layers, and to still maintain as high a yield as possibleduring production.

BRIEF SUMMARY OF THE INVENTION

One aspect of the disclosure provides an electroactive device includinga first conductive layer, a second conductive layer, and one or moreelectroactive layers sandwiched between the first and second conductivelayers. For example, the device may include a first electrode that isone of an electrochromic electrode layer and a counter electrode layer,and a second electrode that is the other of the electrochromic electrodelayer and the counter electrode layer. The electroactive (e.g., anelectrochromic device, an electroluminescent device, a battery, aphotochromic device, a thermochromic device, a suspended particledevice, a liquid crystal display device, a photovoltaic device, a lightemitting diode etc.) device may further include an ion-conductor layerfor conducting ions between the first and second electrodes, and firstand second conductive layers, the first and second electrodes and theion-conductor layer being sandwiched between the first and secondconductive layers.

One or more adjacent layers of the device may include a physicalseparation between a first portion and a second portion of thatconductive layer. The physical separation may define respectivelytapered sidewalls of each of the first and second portions. Theremaining layers of the electroactive device may be formed on the one ormore adjacent layers over the physical separation. In some examples ofthe disclosure, the one or more adjacent layers may include one of thefirst and second conductive layers, and the remaining layers of theelectroactive device may include the other of the first and secondconductive layers. In some examples, the one or more adjacent layers mayinclude at least one of the electroactive layers. In some examples, thereaming layers may include all of the electroactive layers, such thateach electroactive layer is formed above the physical separation.

In some examples of an electrochromic device in accordance with thedisclosure, the one or more adjacent layers may further include one ofthe first and second electrode layers, and the remaining layers of theelectroactive device may include the other of the first and secondelectrode layers and the ion conductor layer. In some further examples,the one or more adjacent layers may further include one of the first andsecond electrode layers and the ion conductor layer, and the remaininglayers of the electroactive device may include the other of the firstand second electrode layers. In yet further examples, the remaininglayers of the electroactive device may include the ion conductor layerand both of the first and second electrode layers.

In some examples, the one or more adjacent layers may be at least abouttwice as thick as the remaining layers of the electroactive (e.g.,electrochromic, etc.) device that are between the scribed adjacentlayers and the other of the first and second conductive layer (i.e., theconductive layer not scribed at P1, as defined below). In furtherexamples, the one or more adjacent layers may be at least about threetimes as thick as the remaining layers of the electroactive (e.g.,electrochromic, etc.) device that are between the scribed adjacentlayers and the other of the first and second conductive layer (i.e., theconductive layer not scribed at P1, as defined below).

In some examples, one of the first and second electrodes may be formeddirectly above the conductive layer having the physical separation. Thephysical separation between the first and second portions may be filledat least partially by the above electrode.

In some examples, the conductive layer having the physical separationdoes not have melt spots along the tapered sidewalls. In some furtherexamples, the electroactive (e.g., electrochromic, etc.) device mayinclude a substrate, and the conductive layer having the physicalseparation may directly touch the substrate without having delaminationalong the respective tapered sidewalls.

In some examples, each of the tapered sidewalls may have a substantiallylinear profile. In other examples, each of the tapered sidewalls mayhave a substantially Gaussian profile. In further examples, the inclineof each of the tapered sidewalls (i.e., with respect or relative to thesubstrate) may be about 45 degrees or less relative to the plane of thesubstrate such that each sidewall does not exhibit shadowing. In somefurther examples, the electroactive device may further include aphysical separation between the second portion and a third portion ofthe plurality of electroactive layers. That physical separation maydefine a respective tapered sidewall of each of the second and thirdportions

Another aspect of the disclosure provides a method of fabricating anelectroactive (e.g., electrochromic, etc.) device. The method mayinclude providing a substrate and forming one or more adjacent layers ofthe electroactive (e.g., electrochromic, etc.) device on the surface ofthe substrate. The method may further include positioning a laser orother scribing implement towards the substrate. In some examples, thelaser or other scribing implement may be positioned incident the side ofthe substrate having the one or more adjacent layers formed thereon(i.e., the film side). In some examples, the laser may have a pulsewidth of about 100 picoseconds or shorter. The method may furtherinclude removing a portion of the one or more adjacent layers, andforming one or more of the remaining layers of the device over thephysical separation of the one or more adjacent layers.

In some examples, removing a portion of the one or more adjacent layersfrom the substrate using the laser or other scribing implement mayfurther involve forming a physical separation between a first portionand a second portion of the one or more adjacent layers, the physicalseparation defining a respective tapered sidewall of each of the firstand second portions.

In some examples, the pulse width of the laser may be even shorter than100 picoseconds. For example, the pulse width may be about 10picoseconds or shorter. For further example, the pulse width of thelaser may be about 6 picoseconds.

In some examples the wavelength of the laser may be between about 340 nmand about 1070 nm. In further examples, the wavelength may be betweenabout 515 nm and about 532 nm.

Yet a further aspect of the disclosure provides a system for fabricatingan electroactive (e.g., electrochromic, etc.) device. The system mayinclude a housing for containing a substrate on which the device isformed, a deposition system for depositing one or more layers of theelectrochromic device onto the substrate, a laser or other scribingimplement mounted in the housing, a positioning device for moving thelaser beam or other scribing implement relative to the substrate, and acollection system for collecting particulate materials or vaporsgenerated by focusing of the beam on the surface of the substrate. Insome examples, the laser or other scribing implement may be mounted andpositioned incident to the film side of the substrate. In some examples,the mounted and positioned laser may have a pulse width of 100picoseconds or shorter.

In some examples of the disclosure, one or more adjacent layers of theelectrochromic device may be formed on the substrate, a portion of thoselayers may be removed, and one or more of the remaining layers of thedevice may be formed over the one or more adjacent layers, all withoutremoving the substrate from the housing. In further examples, everylayer of the electroactive (e.g., electrochromic, etc.) device which isformed during the first stage of fabrication may be formed withoutremoving the substrate from the housing. In some further examples, eachof the above described steps, including the scribing step, may beperformed in a single continuous vacuum step within the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-section of a typical electrochromic device.

FIG. 2 is another schematic cross-section of a typical electrochromicdevice.

FIG. 3 is a schematic cross-section of an electrochromic device inaccordance with an embodiment of the present disclosure.

FIGS. 4A-4C are each schematic cross-sections showing a close-up of aportion of an electrochromic device each in accordance with anembodiment of the present disclosure.

FIG. 5 is another schematic cross-section of an electrochromic device inaccordance with an embodiment of the present disclosure.

FIG. 6 is a flow chart depicting a process for forming an electrochromicdevice in accordance with an embodiment of the current invention.

FIG. 7 is another flow chart depicting a process for forming anelectrochromic device in accordance with an embodiment of the currentinvention.

FIG. 8 is a block diagram of a system for forming an electrochromicdevice in accordance with an embodiment of the current invention.

FIGS. 9A-9C are schematic cross-sections of electroactive devices, eachin accordance with an embodiment of the current invention.

DETAILED DESCRIPTION

The present disclosure provides an electroactive layer structure havinga reduced amount of electronic leakage between the upper and lowerconductive layers. This structure is to be obtainable by a productionmethod that maintains as high a yield as possible. These objectives areimplemented by providing a properly adjusted laser having a pulse widthon the order of about 100 picoseconds or shorter. In some embodiments,the pulse width may be about 50 picoseconds or shorter. In otherembodiments, the pulse width may be about 10 picoseconds or shorter. Inyet other embodiments, the pulse width may be about 6 picoseconds. Ithas been surprisingly and unexpectedly found that scribing the lowerlayer or layers of the electroactive structure using a laser with apulse width on the order of about 100 picoseconds or shorter optimizesthe amount of spreading of heating across the layer structure during thescribing process. A pulse width of about 100 picoseconds or shorter hasbeen found to be long enough to remove or ablate a portion of the lowerlayers (e.g., in the context of an electrochromic device, the lowerconductive layer, the electrochromic layer, and the ion conductinglayer) from the substrate, yet short enough to avoid delamination of thelower layers from the substrate along the scribe edges due to excessivediffusion of the heat generated during the scribing. By avoidingdelamination along the scribe edges, the structure is less prone tocracking, which in turn leaves the lower conductive layer of thestructure less prone to exposure to the upper conductive layer as aresult of such cracking. Since electronic leakage between the upper andlower conductive layers is often caused by coupling between the upperconductive layer and an exposed portion of the lower conductive layer,avoiding exposure of lower conductive layer also in turn reduces theamount of or possibility of electronic leakage between the twoconductive layers.

Furthermore, a pulse width on the order of about 100 picoseconds orshorter has been found to avoid creating melt spots, which are unlevelridges or caves of heated material that is not removed from theelectroactive structure during the scribing processes. These melt spotsform along the scribe edges (e.g., at least a portion of the melt spotbeing located within 5 microns or less of the upper edge of the scribeedge) due to excessive diffusion of heat generated during the scribing.By using a laser with a shorter pulse width, less unwanted heat isspread across the structure, thus avoiding the creation of melt spotsalong the scribe edges. As a result, the scribed lower layer(s) retain arelatively smooth profile (compared to a layer having melt spots). Thisin turn permits other layers to be deposited on top of those lowerlayers also with relatively smooth profiles, permitting better coverageof the lower conductive layer, and thereby minimizing the possibility ofa pinhole contact or electrical short between the upper and lowerconductive layers along the scribed edges.

The objectives of the present disclosure are further implemented bypositioning the laser incident to the film or stack side (hereinafterreferred to as the “film” side for brevity) of the substrate on whichthe electroactive structure is formed, as opposed to incident to thesubstrate side (i.e., the side of the substrate opposite theelectroactive structure). A laser beam emitted from a laser positionedopposite the film side of the substrate must penetrate through thesubstrate and any other intervening layers in order to scribe thematerial formed on the film side. In such situations, the beam is proneto be blocked, scattered, or defocused by bubbles or solid inclusions,which are common in ordinary quality float glass, such as what istypically used in windows for buildings. Blockage of the beam can resultin a portion of the material not being scribed, which in the case of thelower conductive layer, may lead to a conductive bridge (i.e., a short)between the isolated portions of the layer. By contrast, a laser beamemitted from a laser positioned incident to the film side of thesubstrate is not prone to such blockages, and therefore is less prone toleaving behind a conductive bridge in the lower conductive layer.

Furthermore, positioning a laser having a varying energy profileincident to the film side of the substrate has been found to enable goodstep coverage of the film layers between the upper and lower conductivelayers. A laser beam emitted opposite the film side of the substrate hasbeen found to form scribe sidewalls having a steep cliff-like profilealong the scribe edges, leaving the lower conductive layer prone toexposure due to poor step coverage by the additional film layers.Exposure of the lower conductive layer in turn can result in shortsbetween the upper and lower conductive layers. By contrast, a laser beamemitted incident to the film side has surprisingly been found to formscribe sidewalls having a tapered profile. The tapered scribe edgesenable better step coverage so that no portion of the lower conductivelayer is left exposed, which in turn means a lower likelihood of shortsbetween the upper and lower conductive layers.

Thus, using a laser having a pulse width of about 100 picoseconds orshorter, and/or positioning the laser incident to the film side of thesubstrate, results in a significant reduction of breakages, pinholecontacts, or other causes of exposure between the upper and lowerconductive layers. In combination, positioning a laser having a pulsewidth of about 100 picoseconds or shorter incident to the film side ofthe substrate can result in even more dramatic reduction of suchdefects, and has been shown to virtually eliminate shorting between theconductive layers entirely, resulting in better operation (e.g.,coloring in an electrochromic device) and improved energy efficiency,compared to a device having a conductive layer scribed by a laser havinga 1 ns pulse width and positioned opposite the film side of thesubstrate.

While above described improvements are broadly applicable to manyscribed thin film electroactive stacks (e.g., electrochromic devices,batteries, photochromic devices, thermochromic devices, suspendedparticle devices, liquid crystal display devices, photovoltaic cells,light emitting diodes, etc.), regardless of the relative thickness ofthe respective conductive and electroactive layers, the implementationsdescribed in present disclosure are especially beneficial whendepositing relatively thin layers on top of relatively thick scribedlayers. For instance, using the electroactive layers of anelectrochromic device as an illustrative example, if a scribedtransparent lower conductive layer of the device is thicker than theelectrode layers and ion conducting layer of the device, thenimperfections (e.g., delamination, asperities, cracks, melt spots, etc.)created during the scribing of the lower transparent conductive layer orlayers may not be fully or evenly covered by the other layers formed ontop, thereby leaving the lower transparent conductive layer exposed tothe upper transparent conductive layer, leading to electronic leakage inthe device. While this leakage can be tolerated or compensated up to acertain point in the device, this leakage becomes a much greater problemwhen the scribed layer or layers are about twice as thick or more thanthe unscribed layers formed on top, and an even greater problem when thescribed layer or layers are about three times thicker than the unscribedlayers formed on top. As such, the improvements of the presentdisclosure are especially beneficial for, albeit not limited to,electroactive layer structures having one or more scribed layers thatare about twice as thick, three times as thick, or more than three timesas thick as the unscribed layers (not including the upper conductorlayer) formed on top of the scribed layers).

In the case of an electrochromic layer structure, reducing the risk ofproducing shorts in the electrochromic layer structure furthereliminates the need for forming additional dielectric layers above thelower conductive layer. An advantage to omitting these additionaldielectric layers from the layer structure is that processing of thestructure can be performed with only a single pass of the substrate (or“workpiece”) through the initial coater. Generally, in order to form theadditional dielectric layers to improve step coverage, the workpiecemust be transferred out of the initial coater, where the lowerconductive layer is formed and scribed, to a different coater, where thedielectric layers are formed, and then back to the initial coater, wherethe remaining initial layers (e.g., the electrochromic electrode layer,the ion conducting layer, etc.) are formed Eliminating the additionaldielectric layers reduces exposure of the workpiece to the outsideenvironment (which normally occurs during transfer), thereby improvingyield and minimizing the risk of defects to the device during processing(e.g., scratches, edge chips, accumulated particles on the surface ofthe workpiece, other mechanical damage). Even if the additionaldielectric layers would be deposited in the same coater, eliminating theadditional dielectric layers would reduce the processing time perworkpiece.

In accordance with the present invention, FIG. 3 illustrates a portionof a solid-state electroactive device 30, in cross-section, having animproved film structure. For purposes of illustrative clarity, theelectroactive device 30 depicted in FIG. 3 is an electrochromic devicesimilar to the device depicted in FIGS. 1 and 2. However, it will berecognized that the present invention is similarly applicable to othertypes of scribed electroactive devices, as well as other electrochromicdevices with different stacks or film structures (e.g., additionallayers). With regard to the electrochromic device 30 of FIG. 3, thatdevice is similar to the device of FIGS. 1 and 2 only to the extent thateach of the aforementioned layers, 11-15 are present in the device ofFIG. 3 (as layers 31-35). The device of FIG. 3 differs from the devicedepicted in FIGS. 1 and 2 to the extent that the sidewall profile of thescribe at location P1 is shaped differently and has different propertiesor characteristics. For example, whereas the sidewall profile of thescribe in FIGS. 1 and 2 is substantially vertical or cliff-like, theprofile in FIG. 3 is tapered. For further example, although not depictedin the figures, the lower conductive layer of the device of FIGS. 1 and2 is subject to delamination and melt spots along the scribe edges,whereas the improved device of FIG. 3 does not have delamination defectsor melt spots.

In FIG. 3, lower conductive layer 35 is formed on substrate 36 andincludes a first portion coupled to a first busbar 38 and a secondportion coupled to a second busbar 39. The first portion and secondportion are physically separated from one another at location P1 by thescribe. The physical separation is covered and filled, either completelyor partially, by the remaining layers of the electrochromic device,which include the electrode layer 34 formed directly thereon (which maybe either the electrochromic electrode layer or the counter electrodelayer), the ion conductor layer 33, the other electrode layer 32 (whichmay be the other of the electrochromic electrode layer and the counterelectrode layer), and the upper conductive layer 31. Because of thetapered profile of the scribe sidewalls, which is relatively smoothcompared to the scribe sidewalls of the device in FIGS. 1 and 2, theelectrode layer 34 provides improved step coverage along the scribe edgeover the lower conductive layer. Whereas, the ion conducting layer 13shown in FIG. 2 reaches almost to the sidewall of the lower conductivelayer 15, the electrode layer 34 in FIG. 3 maintains improved separationbetween the ion conducting layer 33 and the lower conductive layer 35.Moreover, the electrode layers 32 and 34, and the ion conductor layer 33sandwiched in between, collectively provide improved step coverage alongthe scribe edge over the lower conductive layer 31 so that there are nocurrent leaks or shorts between the respective conductive layers 31 and35.

In the example of FIG. 3, the scribe sidewalls at location P1 have alinearly tapered profile. However, other profiles (e.g., Gaussian ornormal distribution curve-shaped, substantially Gaussian or otherwisecurve-shaped, etc.) may be achieved by adjusting the spatial beam energyprofile of the laser. In some examples, each tapered sidewall mayprovide a smooth transition between the surface of the scribed layersand the surface of the substrate. For instance, each tapered sidewallmay have a rounded upper edge. For further instance, the overall slopeof each tapered sidewall may be about 45 degrees with respect to theplane of the substrate. In some examples, in order to minimize the riskof shadowing, each tapered sidewall could be formed such that no sectionof the sidewalls would have a slope steeper than 45 degrees with respectto the plane of the substrate.

FIGS. 4A-4C depict some possible sidewall profiles that may be achieved.For example, FIG. 4A depicts a close-up of the linear profile of FIG. 3.For further example, FIG. 4B depicts a substantially Gaussian (curved)profile with curved sidewall edges. For yet further example, FIG. 4Cdepicts a profile having both linear and curved properties. In someexamples, the energy profile of the beam may be smoothly varied.

The present disclosure is similarly applicable to electroactive devicesin which multiple layers, and not only the lower conducive layer, arescribed. For example, FIG. 5 illustrates a portion of anothersolid-state electrochromic device 50, in cross-section, having anotherimproved film structure. The device 50 of FIG. 5 is similar to thesolid-state device depicted in FIG. 3 to the extent that each of theaforementioned layers, 31-35 are again present in the device of FIG. 5(as layers 51-55). The device of FIG. 5 differs from the device depictedin FIG. 3 to the extent that the electrode layer directly adjacent tothe lower conductive layer, and the ion conducting layer, have beenscribed along with the lower conductive layer. Comparable to FIG. 3, thesidewall profiles of the scribe at location P1 is tapered. Also, like inFIG. 3, each of the scribed layers of the device in FIG. 5 does not havedelamination defects or melt spots.

In FIG. 5, each of the lower conductive layer 55, first electrode layer54, and ion conducting layer 53, is formed on substrate 56 and includesa first portion coupled to a first busbar 58 and a second portioncoupled to a second busbar 59. The first portion and second portion ofeach layer are physically separated from one another at location P1 bythe scribe. The physical separation is covered and filled, eithercompletely or partially, by the remaining layers, which include theelectrode layer 52 (which may be either the electrochromic electrodelayer or the counter electrode layer) and the upper conductive layer 51.Because of the tapered profile of the scribe sidewalls, which isrelatively smooth compared to the scribe sidewalls of the device inFIGS. 1 and 2, the electrode layer 52 provides improved step coveragealong the scribe edge over the lower conductive layer 55 so that thereare no current leaks or shorts between the respective conductive layers51 and 55.

In the example of FIG. 5, the lower conductive layer, electrochromicelectrode layer, and ion conductor layer are more than about twice asthick as the counterelectrode layer. In other examples of thedisclosure, the lower conductive layer, electrochromic electrode layer,and ion conductor layer may be more than about three times as thick asthe counterelectrode layer. In yet other examples, the lower conductivelayer and one or more other scribed adjacent layers may be about twiceas thick or more than the layers deposited over the scribed layers andunderneath the upper conductive layer. In even further examples, thelower conductive layer and one or more other scribed adjacent layers maybe about three time as thick or more than the layers deposited over thescribed layers and underneath the upper conductive layer. In any of theabove examples, it may be especially beneficial to scribe the deviceusing a laser having a 100 picosecond pulse width, a laser (or otherscribing implement) incident to the film side of the substrate, or both.

Also provided in the present disclosure are methods of fabricating anelectroactive device having the above described improvements. Thecomposition or type of layers which are deposited may be varied in orderto achieve the desired results without departing from the teachings ofthe present invention.

FIG. 6 provides a flow diagram 600 that illustrates a process by whichthe device 30 may be formed. At block 602, a substrate or workpiece onwhich the device will be formed or fabricated is provided. The substratemay be an ordinary piece of float glass, as is generally used inbuilding windows, borosilicate glass, or other glass panes such as forautomotive or aircraft applications. The substrate may be annealed, heatstrengthened, thermally tempered, or chemically strengthened. Thesubstrate may further include other materials suitable for the type ofdevice being fabricated, including many transparent materials such asdiamond, aluminum oxide or sapphire, and rigid or flexible polymers.Additionally, opaque materials with surfaces smooth enough to allowspecular reflection may be used, when polished or coated to form areflective background to the electroactive films, resulting in areflective electroactive device. This could include metals with polishedsurfaces, and reflective metal or dielectric coatings on semiconductorsor dielectrics, such as carbon, silicon, silicon carbide, galliumarsenide, or boron oxide.

At block 604, one or more adjacent layers of the electroactive device,including a layer of conductive material, such as indium tin oxide, areformed on the surface of the substrate. The layers may be deposited suchthat each layer extends continuously from the first busbar to the secondbusbar of the device. In some embodiments, the layers may be only theconductive layer. In other embodiments, the layers may further includean electrode layer formed directly above and adjacent to the conductivelayer. In yet further embodiments, the layers may include an ionconducting layer formed above the electrode layer. In a preferredembodiment, the materials comprising a conductive layer are depositedvia sputtering onto a transparent substrate to form a transparentconductive layer.

At block 606, a scribing implement is positioned incident to the side ofthe substrate having the one or more adjacent layers formed thereon. Thescribing implement may be capable of scribing the layers using one ofseveral different methods, including laser scribing, mechanical abradinginvolving, for example, use of a diamond, ruby or stainless steel tip,electrical discharge machining, or chemical etching, or another suitableremoving processes known in the art (“cutting”). The scribing implementmay be mounted in the deposition (e.g., coating) chamber. If thescribing implement is a laser, positioning of the laser may involvefocusing a laser beam of the laser at location P1 of the substrate.

At block 608, a portion of the one or more adjacent layers is removedusing the scribing implement. In some embodiments, the layers mayscribed or cut at location P1. The scribe may extend the entire lengthof the substrate, i.e., from one end of the substrate to the oppositeend, normal to the location P1 shown in the cross-section of FIG. 3. Thelinewidth of the scribe may be about 25 microns or more. In someembodiments, a scribe having a greater linewidth, or more than onescribe, may be performed around location P1 in accordance with thetechnology of copending U.S. application Ser. No. 13/950,791, thedisclosure of which is hereby incorporated in its entirety herein. Forexample, multiple identical scribes may be formed in the scribed layersnext to (e.g., parallel to) each other. Such scribing would mitigate therisks of discontinuous laser lines, which could possibly lead to leakage(e.g., due to a local defect). In some examples, each scribe may beseparated by unscribed material in the scribed layers. In otherexamples, the multiples scribes could remove all of the material betweeneach scribe, thereby resulting effectively in a single scribe having arelatively large linewidth compared to each individual scribe.

At block 610, one or more of the remaining layers of the electroactivedevice are formed over the one or more scribed adjacent layers. Forexample, in the electrochromic device of FIG. 3, the remaining layersmay include the electrochromic electrode layer, the counter electrodelayer, an ion conducting layer sandwiched between the two electrodelayers, and an upper conducting layer formed above the other layers.Deposition of these layers may be performed by sputtering, chemicalvapor deposition, or other thin film fabrication methods known in theart, such as those described in copending U.S. application Ser. No.13/950,791. In some embodiments, additional layers may be formed in thelayer structure, such as anti-reflective coating layers, optical tuninglayers, such as those described in U.S. Pat. No. 5,724,177, iontransport layers, such as those described in U.S. Pat. No. 8,004,744,the disclosures of which are hereby incorporated in their entiretyherein. Formation of these layers is further described in, for example,U.S. Pat. Nos. 5,699,192, 5,321,544, 5,659,417, 5,370,775, and5,404,244, the disclosures of which are hereby incorporated by referencein their entirety herein.

In some embodiments, all of the adjacent scribed layers and at least oneof the remaining layers are deposited via magnetron sputter depositionin the same vacuum processing chamber so as to increase devicefabrication manufacturability, meaning that the substrate undergoes onlyone stage in coating the initial layers in the fabrication process ofthe device, that the yields are likely to be improved as a result ofreduced handling, and further that the throughput is also likely to beincreased as a result of fewer processing steps. Moreover, depositingall of the initial layers in the same chamber without removing thesubstrate results in a reduction in the number of shorts.

FIG. 7 provides another flow diagram 700 that illustrates anotherprocess by which the device 30 may be formed. The steps described inblocks 702, 704, 708, and 710 are respectively comparable to steps 602,604, 608, and 610 described in connection with flow diagram 600 and aretherefore not repeated here. Flow diagram 700 includes an additionalstep, block 706, which may be performed in lieu or in addition to step606 of flow diagram 600. At block 706, a laser with a pulse width ofabout 100 picoseconds or shorter is provided. In the flow diagram 700 ofFIG. 7, the laser may be positioned either incident or opposite the filmside of the substrate. By positioning a laser having a pulse width of100 picoseconds or shorter incident to the film side of the substrate,both flow diagrams 600 and 700 may be performed together.

Generally, the pulse width of the laser may be selected to optimizedissipation of heat in the device during processing to prevent unwantedspreading of heat, which may cause delamination or melt spots in thelower conductive layer. Such a pulse width is generally about 100picoseconds or shorter, but may vary depending on the materials beingscribed. Generally, pulse widths lasting 1 nm or longer have been foundto cause unwanted spreading of heat, but use of a laser having a shorterpulse width may be beneficial. In some examples, the pulse width of thelaser may be about 50 picoseconds or shorter. In further examples, thepulse width may be about 10 picoseconds or shorter. In yet furtherexamples, the pulse width may be about 6 picoseconds.

The wavelength of the laser may range from about 340 nm to about 1070nm. More particularly, the wavelength of the laser may be selected tominimize absorption of the beam energy by the substrate, and moreparticularly to optimize the ratio of absorption between the lowerconductive layer and the substrate. The optimal wavelength may varydepending on the substrate material and other layer materials. In someembodiments, the lower conductive layer should absorb a high percentageof the energy from the laser, and the substrate should absorb a lowpercentage of the energy. For example, in the electrochromic devicesdescribed in copending U.S. application Ser. No. 13/950,791, it has beenfound that the glass substrates for electrochromic devices have arelatively low absorption of green light, and indium tin oxide on aglass substrate exhibits a higher ratio of absorption. Further, it hasbeen found that light having a wavelength between about 515 nm and about532 nm is preferred in such a device. In other devices using differentmaterials, a laser emitting light having a different wavelength may bepreferred.

FIG. 8 provides a simplified diagram of a system 800 for forming theelectroactive device of the present disclosure. The system 800 includesa housing or chamber 810 for fabrication of the device. The chamber 810may be any standard evaporation chamber or coater known in the art usedfor fabrication of electroactive devices. For example, the chamber 810may be a coater, such as for performing an initial stage of coating theconductive and/or electroactive layers on a substrate. The chamber 810may be operated at either vacuum or under other pressure conditions(e.g., normal atmospheric pressure). Housed within the chamber 810 maybe the film deposition system 801, the laser 803, a positioning device805 for positioning or adjusting the position of beam of the laserrelative to the substrate, the substrate 807, and a collection system809.

The film deposition system 801 may be a magnetron sputter, DC sputter,or RF sputter, or other means for depositing thin films of conductiveand/or insulating materials on a substrate in vacuum conditions. Thelaser 803, as described above, may in some examples have a pulse widthless than about 100 picoseconds. In some embodiments, the positioningdevice 805 may hold the laser in place and/or mount the laser within thechamber, with the laser oriented such that it emits a laser beam at thesurface of the substrate 807. In some examples, the positioning device75 may be configured such that the laser beam is incident to the filmside of the substrate 807. The positioning device 805 may further beconfigured to displace or reorient the laser such that the focused beammay move along the scribe edge on the surface of the substrate 807.

The collection system 809 may be a vent, electrostatic plate, chilledsurface, pipe, or other structure for collecting particulate materialsor vapors generated by focusing of the beam on the surface of thesubstrate. The collection system 809 may further be configured to filterthose particulate materials or vapors, and/or carry them out of thehousing 810. Collection and/or ejection of the particulate materials orvapors is beneficial for preventing materials from being ‘blown’ aroundduring purging, venting, and/or pumpdown of the housing, which in turncould scratch or otherwise damage the substrate and/or film structure.

In one example of the present disclosure, the electroactive device maybe formed without having to remove the substrate from the housing. Forinstance, in forming the electrochromic device of FIG. 3, the substratemay be placed in the housing, a layer of conductive material may beformed on the surface of the substrate, a portion of the layer ofconductive material may be removed using the laser, and at least one ofthe electrochromic electrode layer and the counter electrode layer maybe formed on the layer of conductive material, all without removing thesubstrate from the housing. In some examples, these steps may beperformed in a single continuous vacuum step.

Although each of the above embodiments illustrates a cut at location P1through only the lower conductive layer, it will be understood that thebenefits of using a short pulse-width laser and/or laser positionedincident to the film side of the substrate may be realized in scribesthrough multiple layers of a device, such as through both the lowerconductive layer and the adjacent electrode layer, or further such asthrough the lower conductive layer, the adjacent electrode layer, andfurther through the ion conductor layer(s) adjacent to the electrodelayer. Such scribes are described in, for example, copending U.S.application Ser. No. 13/786,934, the disclosure of which is herebyincorporated in its entirety herein.

As described above, in the case of a scribed electrochromic device, theabove described benefits may be realized in scribes through theconductive layer 911 only, such that the electrode layers and ionconductor layer 912-914 separate the upper and lower conductive layers,915 and 911 respectively (910), or through the conductive layer 921 andone electrode layer 922, such that the emitting layer 923 and the othertransport layer 924 separate the upper and lower conductive layers, 925and 921 respectively (920), or even through the conductive layer 931,one electrode layer 932, and the ion conductor layer 933, such that onlythe other electrode layer 934 separates the upper and lower conductivelayers, 935 and 931 respectively (930). Similarly, in the case of ascribed electroluminescent device, the above described benefits may berealized in scribes through the conductive layer 941 only, such that theinsulating layers and phosphor layer 942-944 separate the upper andlower conductive layers, 945 and 941 respectively (940), or through theconductive layer 951, one insulating layer 952, and the phosphor layer953 (e.g., such that only the other insulating layer 954 separates theupper and lower conductive layers, 955 and 951 respectively) (950). Inthe case of a scribed OLED, the above described benefits may be realizedin scribes through the conductive layer 961 only, such that thetransporting layers and emitting layer 962-964 separate the upper andlower conductive layers, 965 and 961 respectively (960), or through theconductive layer and one transport layer, such that the emitting layerand the other transport layer separate the upper and lower conductivelayers (not shown), or even through the conductive layer, one transportlayer, and the emitting layer, such that only the other transport layerseparates the upper and lower conductive layers (also not shown).Further, in the case of a scribed photovoltaic device, the abovedescribed benefits may be realized in scribes through the conductivelayer 971 only, such that the acceptor/donor layers and pn-junctionlayer 972-974 separate the upper and lower conductive layers, 975 and971 respectively (970), or through the conductive layer 981, one of theacceptor/donor layers 982, and the p-n junction layer 983, such thatonly the other acceptor/donor layer 984 separates the upper and lowerconductive layers, 985 and 981 respectively) (980). Each of theseembodiments is depicted for illustrative clarity in the diagrams ofFIGS. 9A-C.

Also, in each of the above described embodiments in which scribing isperformed incident to the film side of the substrate, such scribing isdescribed as performed with a laser. However, it will be understood thatthe benefits of at least the tapered sidewall edges may be achievedusing other cutting or ablation tools/techniques, such as etching,mechanical abrading, or any other suitable removing processes known inthe art (“cutting”). Furthermore, while the above embodiments aredescribed in connection with a chamber housing a laser, it will beunderstood that the chamber may be equipped with any of these othercutting or ablation tools in order to achieve the tapered sidewall ofthe present disclosure.

Additionally, although each of the above embodiments illustrates devicestructure between only two busbars, it will be understood that the abovedisclosure similarly applies to devices having more than two busbars aswell. In such devices, each of the busbars may be electrically separatedfrom each other by forming the structures as described above. Forming ofeach of the structures may be performed simultaneously or sequentially,and the layers formed between each pair of busbars may be scribed in anyof the manners described above.

Lastly, the embodiments described above and illustrated in the figuresare not limited to rectangular shaped devices. Rather, the descriptionsand figures are meant only to depict cross-sectional views of an deviceand are not meant to limit the shape of such a device in any manner. Forexample, the device may be formed in shapes other than rectangles (e.g.,triangles, circles, arcuate structures, etc.). For further example, thedevice may be shaped three-dimensionally (e.g., convex, concave, etc.).

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

The invention claimed is:
 1. A method of making an electroactive device,the method comprising: providing a substrate; forming a plurality ofelectroactive layers on the substrate, including: forming one or moreadjacent layers of the plurality of electroactive layers on thesubstrate, the one or more adjacent layers formed including a firstconductive layer and a first electrode layer; removing a portion of theone or more adjacent layers formed to define a gap in the one or moreadjacent layers formed, wherein the portion is removed using a laserhaving a pulse width of about 100 picoseconds or shorter; forming one ormore additional layers of the plurality of electroactive layers over theone or more adjacent layers formed after removing the portion of the oneor more adjacent layers formed to define the gap in the one or moreadjacent layers formed, the one or more additional layers formedincluding a second conductive layer and second electrode layer, whereinthe second conductive layer comprises a tapered sidewall formed by thelaser and wherein the second electrode layer directly contacts eitherthe first electrode layer or the first conductive layer, wherein the oneor more adjacent layers is at least twice as thick as the secondelectrode layer.
 2. The method of claim 1, wherein the pulse width ofthe laser is about 10 picoseconds or shorter.
 3. The method of claim 1,wherein the pulse width of the laser is about 6 picoseconds or shorter.4. The method of claim 1, wherein the laser has an operationalwavelength in a range of about 515 nm to about 532 nm.
 5. The method ofclaim 1, wherein the laser is positioned incident to the side of thesubstrate having the one or more adjacent layers formed thereon.
 6. Themethod of claim 1, wherein the gap has tapered sidewalls formed by thelaser.
 7. The method of claim 6, wherein the gap does not have meltspots along the tapered sidewalls.
 8. The electroactive device of claim1, wherein each tapered sidewall comprises a rounded upper edge.
 9. Themethod of claim 1, wherein a portion of the first conductive layer isremoved to define at least a portion of the gap in the one or moreadjacent layers.
 10. The method of claim 9, wherein the first conductivelayer comprising the gap directly touches the substrate withoutdelamination along a sidewall of the gap.
 11. The method of claim 1,wherein the additional layers extend over the gap.
 12. The method ofclaim 1, further comprising disposing a first bus bar and a second busbar immediately over a same one of the first conductive layer and thesecond conductive layer.
 13. A method of forming an electroactivedevice, the method comprising: providing a substrate; forming aplurality of electroactive layers on the substrate, wherein theplurality of electroactive layers includes a first conductive layer, afirst electrode layer, an ion conducting layer, a second electrodelayer, and a second conductive layer, wherein forming the plurality ofelectroactive layers includes: forming one or more adjacent layers ofthe plurality of electroactive layers on the substrate, the one or moreadjacent layers formed including the first conductive layer; removing aportion of the one or more adjacent layers formed to define a gap in theone or more adjacent layers formed; and forming one or more additionallayers of the plurality of electroactive layers over the one or moreadjacent layers formed after removing the portion of the one or moreadjacent layers formed to define the gap in the one or more adjacentlayers formed, the one or more additional layers formed including thesecond electrode layer, the second electrode layer directly contactingat least one of the first conductive layer and the first electrodelayer, wherein the second conductive layer comprises a tapered sidewallformed by the laser, wherein the one or more adjacent layers is at leasttwice as thick as the second electrode layer.
 14. The method of claim13, wherein the second electrode layer contacts both the firstconductive layer and the first electrode layer.
 15. The method of claim13, wherein the second electrode layer contacts the substrate.
 16. Themethod of claim 13, wherein the first electrode layer includes a counterelectrode layer, and the second electrode layer includes anelectrochromic electrode layer.
 17. The method of claim 13, wherein thegap has tapered sidewalls.
 18. The method of claim 13, wherein a portionof the first conductive layer is removed to define the gap.
 19. A methodof forming an electrochromic device, the method comprising: providing asubstrate in a housing, and without removing said substrate from thehousing: forming two or more adjacent layers of the device on thesurface of the substrate, the two or more adjacent layers formedincluding the a first conductive layer and a first electrode layer;removing a portion of the one or more adjacent layers using a laser; andforming one or more additional layers of the device over the one or moreadjacent layers, wherein the at least one of the one or more additionallayers of the device comprises a tapered sidewall formed by the laser,the one or more additional layers including a second electrode layerwherein the second electrode layer directly contacts either the firstelectrode layer or the first conductive layer, wherein the one or moreadjacent layers is at least twice as thick as the second electrodelayer.
 20. The method of claim 19, wherein the gap has taperedsidewalls.